Update 1.6.0 has been released with several new parts. The SLS has had some upgrades and now has payload fairings similar to the Saturn V. Stations now have some more parts, such as the Medbay, Airlock, corridor, Standalone Space Station (or Skylab) and the Cargo Bay.
This update also includes a new premium part, the Transponder Module. This part cannot be unlocked by completing missions. It must be purchased as an add-on.